Human long pentraxin 3, PTX3 or hPTX3 (GENBANK ® Accession Number BD 131701) is a multimeric glycoprotein composed of eight subunits linked by disulphide bridges.
The authors of the present invention have already designed an expression system for the production of PTX3 in HEK293F human cell line. This system is based on a plasmid containing the neomycin resistance gene wherein the PTX3 gene is under the control of a human Ubiquitin C promoter sequence. Such system avoids the potential formation of a chimeric PTX3 derived from endogenous production of PTX3 by a cell line of non-human origin. The best producer isolated clone, named 2F12, was selected among those obtained. A production of about 20 mg/L of PTX3 was obtained, which was not sufficient for commercial production needs.
With the aim to increase PTX3 expression levels, the authors of the present invention have constructed a plasmid in which the PTX3 gene was under CMV promoter control. The plasmid was used to re-transfect the PTX3 expressing clone 2F12. The productivity level detected in the new isolated transfectomas was higher that expected, around 80 mg/L.